Novel perspectives on non-invasive cetacean research using microRNA biomarkers in the exhaled breath (blow)

BLOWOMICS will use the snot (“blow”) of whales and dolphins (cetaceans) as a non-invasive way to develop biomarkers for understanding cetacean physiology and health. Non-invasive biomarkers for cetaceans are currently scarce, and new biomarker development will revolutionize our understanding and management of the health of these wild and charismatic marine resources. BLOWOMICS biomarkers will be developed by utilizing a type of small RNA that can be found in most tissues and body fluids of all organisms, called microRNAs (miRNAs). miRNAs are small molecules that are involved in RNA silencing and regulation of gene expression, and thereby have important biological functions. MiRNA profiles are known to change under different physiological states in a predictable manner and are gaining an emerging interest for early non-invasive disease diagnosis in humans. BLOWOMICS will pioneer this technology in cetaceans. However, the traditional biological matrix in which miRNAs are studied (i.e., blood) is not easily available for collection from large, free-swimming whales. Therefore, BLOWOMICS will characterize miRNAs in the “snot” or “blow” from these animals. The presence and amount of microRNAs will first be studied and compared between individuals of a well-known captive dolphin population in Australia. This will hopefully provide information about the miRNA markers that can indicate an animals’ sex, pregnancy status and, the presence of specific diseases. BLOWOMICS will then validate these biomarkers in large free-swimming whales in Norway. BLOWOMICS biomarkers will be developed in a way that is affordable and easy to use, so that other researchers can reproduce these methods and results can be compared worldwide and will include a curated open access database for cetacean miRNAs. The calculated costs of a BLOWOMICS biomarker will be at 10% the costs of traditional analyses.

In human and veterinary medicine, blood is the most valuable sample to use to assess health status, as most health variables from multiple metabolic processes and organs are reflected there in real time. However, there is no practical method to obtain blood samples from large free-swimming cetaceans. While possible for smaller species, it obligates the capture and restraint of these individuals, which can be logistically challenging for researchers, and stressful for the animal. Thus, the most widely used sampling technique for free-ranging cetaceans remains remote tissue biopsying, which is considered invasive, even if minimally, as it causes a small lesion on the animal. Nevertheless, in recent years, novel and promising ways of examining whale health are being developed using cetacean exhaled breath or “blow”, collected non-invasively - from the detection of hormones and other metabolites, microbiological studies, genetic markers to determine sex, species, or individual identification and there is strong potential to be used for the discovery of new biomarkers of health. In human medicine, the potential of microRNAs (miRNAs) as non-invasive biomarkers in biological fluids, including exhaled breath condensates, has been well established20. As such many model species already have miRNAomes available; however, miRNAs have not been carefully studied in wildlife species, including cetaceans. The development of miRNAs as novel non-invasive biomarkers of cetacean physiology could revolutionise the field. BLOWOMICS Thus, aims to: 1) provide a well-defined and characterised miRNAome for different tissues of cetaceans; 2) test the potential of using miRNA biomarkers in cetacean blow to address key knowledge gaps in free-swimming large cetaceans and 3) develop an ‘open access’ database for cetacean miRNA resources to facilitate data sharing and advancements worldwide.